Valve, Inlet (non O.e. Alternative) Gl1000 1979 (z)

Check the Valve guides for wear (the most likely reason for smoking on start up) when inspecting the valves, Valve seats, retainers, rockers, rocker-shafts, & cam-shafts for wear or damage.
The valves and springs should be replaced as a matter of course, the other items depends on their condition - if you are in any doubt, then replacement with new parts is probably the best course of action.
Other related parts you may wish to consider:

06112371000P
14211371300
14611371000
14611463000
14631371000
14642371000
14711371000
14721371000P
14751611003
14761611003
14771551020
14775300000
14775410010
9440125140
90701283000

Add as many new parts as you wish to the same shopping cart, new Valve stem seals 12209MB9003 & retention cotters 14781551000 for example, and still only pay the same single fixed price shipping cost.

Please be aware that this component may have other applications on other Honda machinery, so always check the part-number is right for your model prior to ordering.

Pro-workshop gasket sealant 08C70K0234M easy to apply with perfect results.